1 3 Facies (2017) 63:8 DOI 10.1007/s10347-016-0491-7 ORIGINAL PAPER Upper Pleistocene cold‑water corals from the Inner Sea of the Maldives: taphonomy and environment Jesús Reolid 1 · Matías Reolid 2 · Christian Betzler 1 · Sebastian Lindhorst 1 · Martin G. Wiesner 1 · Niko Lahajnar 1 Received: 14 July 2016 / Accepted: 31 December 2016 / Published online: 13 January 2017 © Springer-Verlag Berlin Heidelberg 2017 factors which inhibit modern cold-water coral growth in the inter-atoll channels. Keywords Lophelia · Coral rubble · Epibionts · Oxygenation · Indian Ocean Introduction Cold-water coral buildups host communities of associated animals that are distinct from the surrounding background deep-sea fauna and have high species diversity and some- times a high level of endemism (Henry and Roberts 2007; van Soest et al. 2007; Mastrototaro et al. 2010; Morigi et al. 2012; Schöttner et al. 2012). The biodiversity associated with these ecosystems is comparable to that found in tropi- cal coral reefs (Roberts et al. 2006, 2009). Cold-water coral buildups occur in a variation of settings such as on conti- nental slopes, seamounts, plateaus, ridges, and submerged sides of oceanic islands (Rogers 2004; Davies et al. 2008; Roberts et al. 2009; Wienberg and Titschack 2015). Cold-water corals are associated with permanent or epi- sodically strong currents, because the currents supply food and disperse eggs sperms and larvae, remove waste prod- ucts and winnow the sediment thus avoiding the burial of corals (Rogers 2004). However, recent studies have indi- cated that removal of waste products and winnowing of sediment by currents seems are irrelevant aspects for cold- water coral growth (Larsson and Purser 2011; Purser and Thomsen 2012; Titschack et al. 2015). But the requirement for a strong current influences the distribution and growth form of corals at all scales (Rogers 2004; Davies et al. 2008). Cold-water corals are usually associated to food supply that is commonly driven by the interplay of surface water productivity, the bottom current regime (e.g., internal Abstract Cold-water corals of the Late Pleistocene (21,400–22,500 BP) are recorded from the sea-bottom of two inter-atoll channels (Kardiva Channel at 457-m depth and Malé Vaadhoo Channel at 443-m depth) of the eastern row of the Maldives archipelago. Coral assemblages are composed mainly by Lophelia pertusa and secondarily by Madrepora oculata and Enallopsammia rostrata. These cold-water coral patches are places where the benthic life, mainly sessile, is concentrated, which is clearly absent off-rubble patches. The main epibionts are tube-dwelling polychaetes (mainly Spirorbis and Serpula), bryozoans, siliceous sponges, barnacles, gorgonids, solitary corals, encrusting foraminifera, and microbial mats. The analy- sis of epibionts assemblages shows different biocoenoses between both studied sites as well as a dependency of the epibiont coverage with regard to the coral genus. Some living benthic organisms such as brachiopods, bivalves, gastropods, barnacles, and ophiuroids find refuge among coral branches. The common record of juvenile specimens of vagile organisms such as small ophiuroids, is probably related to the nursery function of the cold-water corals in spite they are fossils. Environmental requirements of Recent cold-water corals (Lophelia, Madrepora and Enal- lopsammia) differ of conditions at both sampling sites with sensibly lower oxygenation degree and density of waters than needed for cold-water corals. Therefore, it is proposed that the present-day oxygen and density conditions are the * Matías Reolid mreolid@ujaen.es 1 Institute of Geology, Universität Hamburg, Bundesstraße 55, 20146 Hamburg, Germany 2 Departamento de Geología, Universidad de Jaén, Campus Las Lagunillas sn, 23071 Jaén, Spain